The noisy neighbors have started their 2013-14 campaign with a £90million spending spree, acquiring Stefan Jovetic, Alvaro Negredo, Jesus Navas and Fernandinho.

However, City are going to need one more key signing if they hope to finally move past their Champions League failures.

Jovetic and Negredo were brought in to replace the always controversial duo of Carlos Tevez and Mario Balotelli. Navas and Fernandinho can be looked at to push the already formidable midfield of Yaya Toure, David Silva, James Milner and Javi Garcia.

However, one area City have failed to address is defense, as their back line looks different, but for all the wrong reasons.

Enter Pepe.

City enter this campaign with a very thin defense. Kolo Toure was released to join Liverpool for free. The oft-injured Maicon was offloaded after less than a year in sky blue. Finally, fan favorite Matija Nastasić was injured in last month's Asia Trophy final.

Despite still having Vincent Kompany and Joleon Lescott, Pepe would provide exactly what City need: a strong defender with Champions League experience in spades.

Pepe has featured heavily for Real Madrid sides that have experienced tons of success. The addition of the Portuguese international would give City a much-needed defensive option, as they have only three legitimate central defenders.

Pepe, who could feature at a defensive midfield position, would also bring a new level of toughness that would certainly fit with the Premier League mentality, although he does can go overboard on occasion.

All of this is not lost on new boss Manuel Pellegrini, as the Chilean manager has admitted that another defensive signing is exactly what City need.

The Citizens were battered 3-1 in Helsinki by Premier League rivals Arsenal over the weekend, leaving Pellegrini worried about his squad's defending.

“We had some problems ­defending and we will try to improve that this week,” Pellegrini stated after the game, according to Mirror.co.uk. “We will see this week what we need. If we buy someone, then OK. If not, I think we have got the squad to solve our ­problems. We have conceded too many in preseason and will have to arrange it.”

Pellegrini has also come out and referenced Pepe by name, a move showing that City have genuine interest in the Real Madrid man.

“I just said that we will see what happens in this month and during August," said Pellegrini according to Mirror.co.uk. "But I’m not talking about specific names because it’s better for us, so I don’t talk about Pepe or any other names.”

The gesture hasn't been lost on Pepe, who came out and addressed transfer rumors last week during Madrid's preseason tour of the United States.

"I'm a professional. They left a lot of things at the end of last season but I have a contract to fulfill," said the Portuguese international according to Sky Sports. "I'm talking to the president of Madrid and my representatives to see what will happen."

With that said, look for City to use the month of August to court Pepe, as he looks to be exactly the signing that City need to fill their defensive holes. If Pepe is brought into the fold, expect City to challenge for titles both domestic and European, as they will finally fill out what appears to be one of the strongest squads in Europe.

Would Pepe guarantee City Champions League Success? Have your say with a comment or tweet @r_tolmich with your viewpoint!